This invention relates to the fields of computer systems and data communications. More particularly, an apparatus and method are provided for determining a suitable inter-packet gap, of variable length, based on the size of a packet.
One characteristic of packet-based communications is the delay between transmission of successive packets; this delay is commonly known as the inter-packet gap (IPG). Ethernet and other communication networks and protocols generally call for gaps of specific durations or lengths, which may be measured in bytes. For example, the standard delay between packets in Ethernet (as specified in IEEE standard 802.3ae) is twelve bytes. As long as the communication rates of the networks are within the expected range, the standard delay should be sufficient to allow switches, gateways, end stations and other entities to process the packets.
However, when packets cross network boundaries or are translated from one protocol or system to another, and particularly when different communication rates are encountered on either side of the boundary, an inter-packet gap applied on one side may be insufficient on the other. For example, when transferring packets from an Ethernet network operating at 10 gigabits/sec to an OC-192 SONET (Synchronous Optical Network) WAN (Wide Area Network) operating at approximately 9.45 gigabits/sec, the standard Ethernet IPG of twelve bytes may not leave sufficient time for an OC-192 entity (e.g., switch) to handle long packets.